Implantable medical device connector

ABSTRACT

Disclosed is an implantable medical device including a connector block that allows varied lead configurations to be used with a single connector block and implantable medical device assembly. The connector block is configured with one or more lead insertion lumens that are open at both ends, such that each end of the lead insertion lumen may receive a separate lead. The circuitry within the implantable medical device is configured to allow the delivery of electrical pulses from a pulse generator within the implantable medical device to two separate leads inserted within opposite ends of a single lead insertion lumen.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims benefit of copending U.S.Provisional Patent Application Ser. No. 61/221,953 entitled “ImplantableMedical Device Header or Connector for Connecting Leads to a PowerSource”, filed with the U.S. Patent and Trademark Office on Jun. 30,2009 by the inventor herein; and is likewise based upon and claimsbenefit of copending U.S. Provisional Patent Application Ser. No.61/226,393 entitled “Implantable Medical Device Header or Connector forConnecting Leads to a Power Source,” filed with the U.S. Patent andTrademark Office on Jul. 17, 2009; both of which specifications areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the field of implantablemedical devices, such as electrical stimulators, defibrillators, andpacemakers, and more particularly to a connector assembly for suchdevices configured to couple leads to the implantable device.

BACKGROUND OF THE INVENTION

Implantable medical devices (“IMD”) are used today for variousapplications to deliver electrical pulses from a pulse generator withinthe IMD, through an electrical lead connected to the IMD, to a targetedlocation within a patient's body. For instance, pacemakers are used todeliver electrical pulses generated within a pulse generator through anelectrical lead to a patient's heart to maintain proper rhythm. In orderto deliver those pulses, the electrical pulse from the generator isdelivered through a lead connector assembly to a plurality of electricalcontacts at one end of the lead, which lead then carries the electricalpulses to electrical contacts at the opposite end of the lead which arepositioned adjacent the portion of the patient's heart that is to bestimulated.

Similarly, IMD's may be used in neurological applications, such as fordeep-brain stimulation and spinal cord simulation, in which leadsdeliver electrical pulses generated in the IMD to targeted portions of apatient's brain or spinal cord.

In still other applications, leads may be used to sense particularconditions within a patient's body, and relay that sensed condition backto a processing unit within the IMD.

Many IMD's include a housing that houses the circuitry of the IMD, aconnector block that connects the lead or leads to the IMD, and one ormore leads inserted into the connector block to transfer electricalpulses generated within the IMD to the targeted portion of the patient'sbody. Many such connector blocks include female receptacles into whichthe male end of a multicontact lead may be inserted; however, the femalereceptacles are provided on only one end of the connector block. Thisconfiguration of the female receptacle of the header or connector mayhave a limiting effect on the number and types of leads that may beoperated with a single implantable medical device. For instance, aconnector block might have two receptacles, each providing 12 electricalcontacts configured to receive a 12-contact lead. This configuration canbe useful where the patient's condition requires the delivery ofelectrical stimulation using 12-contact leads, such as a 12-contactpercutaneous electrode. If, however, the patient's condition changessuch that an alternate configuration is desired (such as using 38-contact leads to more disparately apply the electrical pulses across abroader area), an alternative connector block must be provided thatprovides 3 8-contact receptacles. Requiring such a change of the IMD toreceive an alternative lead configuration can be quite expensive andclearly uncomfortable and undesirable for the patient. Likewise, asdoctors may have varied preferences for how and in what configurationelectrical pulses should be delivered to a targeted portion of apatient's body (based on a particular patient's diagnosed condition),providing separate connector blocks for every possible configuration thedoctor might come across can likewise become quite costly, as itsignificantly complicates the inventory that the doctor must maintain.

Therefore, it would be desirable to provide an improved connector blockfor an implantable medical device that could be variably configured toadapt to varied clinical conditions so as to allow the delivery ofelectrical pulses from an IMD in such varied clinical conditions usingonly a single, standard connector block.

Moreover, in some operative environments, operative space may be limitedfor inserting a lead longitudinally into the connector block on the IMD.In such environments, it would be desirable to provide an improvedconnector block that could allow insertion of leads into the connectorblock without requiring their longitudinal insertion, and that wasotherwise configurable to minimize the amount of space that must beavailable in the operative environment to engage the leads with theconnector block assembly.

SUMMARY OF THE INVENTION

Disclosed is an IMD including a connector block that allows varied leadconfigurations to be used with a single connector block and IMDassembly. The connector block is configured with one or more leadinsertion lumens that are open at both ends, such that each end of thelead insertion lumen may receive a separate lead. The circuitry withinthe IMD is configured to allow the delivery of electrical pulses from apulse generator within the IMD to two separate leads inserted withinopposite ends of a single lead insertion lumen.

With regard to an aspect of a particularly preferred embodiment of theinvention, a connector assembly for removably attaching a plurality ofleads to an implantable medical device is disclosed, comprising aconnector block housing having a first end and a second end, theconnector block housing further comprising a lower casing and an uppercasing removably attached to the lower casing, and at least one leadinsertion lumen extending through the connector block housing from thefirst end to the second end and providing two points of entry throughthe connector block housing and into the lead insertion lumen, the leadinsertion lumen further comprising a plurality of electrical contactsdisposed within the lead insertion lumen and configured to direct anelectrical pulse from a pulse generator assembly to a lead positionedwithin the lead insertion lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

The numerous advantages of the present invention may be betterunderstood by those skilled in the art by reference to the accompanyingdrawings in which:

FIG. 1 is an exploded perspective view of an implantable medical devicein accordance with an exemplary embodiment of the present invention;

FIG. 2 is a front view of the implantable medical device of FIG. 1;

FIG. 3 is a side view of the implantable medical device of FIG. 1;

FIG. 4 is a perspective view of an application of the implantablemedical device of FIG. 1; and

FIG. 5 is a perspective view of a connector block according to oneembodiment of the invention.

FIG. 6 is an exploded, perspective view of an implantable medical devicehaving a modular connector block;

FIG. 7 is an exploded, perspective view of an implantable medical devicehaving a modular connector block and an adapter within the connectorblock; and

FIG. 8 is an exploded, side view of an implantable medical device havinga modular connector block and an adapter within the connector block.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of a particular embodiment of theinvention, set out to enable one to practice an implementation of theinvention, and is not intended to limit the preferred embodiment, but toserve as a particular example thereof. Those skilled in the art shouldappreciate that they may readily use the conception and specificembodiments disclosed as a basis for modifying or designing othermethods and systems for carrying out the same purposes of the presentinvention. Those skilled in the art should also realize that suchequivalent assemblies do not depart from the spirit and scope of theinvention in its broadest form.

An IMD is described herein, such as an implantable pulse generator,which includes a connector block that allows varied lead configurationsto be used with a single connector block and IMD assembly. The connectorblock has one or more insertion lumens extending through the connectorblock, providing two insert openings into which two separate leads maybe inserted to separately receive electrical pulses from a pulsegenerator within the IMD. The pulse generator is preferably configurableso as to allow the delivery of appropriate pulses to the appropriateelectrical contacts within the insertion lumen, thus allowing theintended stimulation signal to be transmitted through the intended leadsand out to the stimulating contacts at the end of each such lead. Suchconfiguration allows for varied lead configurations to be used with asingle IMD, thus minimizing the need to maintain large inventories ofvaried connector block configurations and minimizing the extent ofinvasion into a patient's body if lead modifications must be made afterthe IMD has been implanted.

As shown generally in the exploded perspective view of FIG. 1, anexemplary embodiment of a biologically inert IMD 100 is shown includinga pulse generator assembly 104 and a connector block 150 according tocertain aspects of the present invention. In exemplary embodiments,connector block 150 receives the insertion ends of one or more leads 200and 210, thereby electrically connecting leads 200 and 210 with pulsegenerator assembly 104, and in turn allowing an electrical pulse to passfrom pulse generator assembly 104 to an electrode, a contact pad, oranother connector in series, connected to the opposite end of each ofthe leads.

While FIG. 1 particularly shows a connector block 150 in the form of aheader which is joined to the body of a pulse generator, those ofordinary skill in the art will recognize that this illustrates only onepossible configuration of the invention. Alternatively, a connectorblock embodying the invention could be joined to the end of an extensioncable or lead(s), remote from the pulse generator. Any number of suchconnectors could be assembled in series, and by the variety of assemblyarrangements which are possible, they could reconfigure or remap subsetsof contacts and/or leads.

In the current embodiment, connector block 150 includes two insertionlumens 164 and 174 configured to receive leads 200 and 210 within eitheror, simultaneously, both open ends of a single insertion lumen.Insertion lumens 164 and 174 are configured to receive and removablyhold the insertion ends of electrical leads 200 and 210 in aconventional manner, such as (by way of non-limiting example) a bal sealproviding a physical and electrical connection to the multipleelectrical contacts within each of insertion lumens 164 and 174 througha compressive contact, as are known to those of ordinary skill in theart. Those of ordinary skill in the art will also readily recognize thatother mechanisms may likewise be used to mechanically hold leads 200 and210 within insertion lumens 164 and 174 without departing from thespirit and scope of the instant invention, such as variously configuredresilient, compression fit mechanisms, various snap-fit connectionmechanisms, friction fit mechanisms, threaded connection mechanisms, andthe like. As shown in the exemplary embodiment of FIGS. 1-3, a pluralityof set screws 118 are provided to engage with the inserted end of theleads once they are positioned within the insertion lumens. Alternativesecondary connector mechanisms that assist to ensure the secureconnection of the lead within the insertion lumen may also be employed.For instance, various types of set pins and/or O-ring mechanisms may beemployed.

Likewise, while only two insertion lumens are shown in the exemplaryembodiment of FIG. 1, those of ordinary skill in the art will recognizethat more or fewer insertion lumens may be provided in a connector block150 without departing from the spirit and scope of the instantinvention.

-   -   In the exemplary embodiment of FIG. 1, each of insertion lumen        164 and insertion lumen 174 is provided first and second        openings in connector block 150 configured to receive the        proximal end of a lead, such as leads 200 and 210. More        particularly, the first insertion lumen 164 is provided a first        opening 166 and a second opening 168, with insertion lumen 164        extending through connector block 150 between first opening 166        and second opening 168. Similarly, the second insertion lumen        174 is provided a first opening 176 and a second opening 178,        with insertion lumen 174 extending through connector block 150        between first opening 176 and second opening 178. The first and        second openings of the first and second insertion lumens may be        variously sized and may be positioned at various locations        within connector block 150. Thus, each of the insertion lumens        includes an open first end and an open second end, thereby        establishing two open-ended insertion lumens within the body of        the connector block 150.

As shown in the exemplary embodiment of FIG. 1, each of connectionlumens 164 and 174 extends the length and through the interior ofconnector block 150. In the current embodiment, disposed along each ofconnection lumens 164 and 174 are a plurality of electrical contacts192. In the exemplary embodiment of FIG. 1, each of first and secondconnection lumens 164 and 174 contain 12 electrical contacts. In analternative preferred embodiment, each connection lumen may include 24contacts. As will be apparent to those of ordinary skill in the art, thenumber of contacts disposed in a connection lumen may vary from theforegoing as required for a particular application without departingfrom the spirit and scope of the invention. The configuration anddimensional characteristics of the electrical contacts within eachconnection lumen may vary to accommodate various technologies known tothose skilled in the art.

In the exemplary embodiment of FIG. 1, connector block 150 ishermetically sealed to a housing 106, which housing in turn containspulse generator assembly 104. The plurality of contacts 192 connect withcircuitry of the pulse generator assembly 104 allowing the electricalstimulation to pass through to the plurality of contacts 192. Moreparticularly, pulse generator 104 preferably includes a power source andelectronic circuitry configured to transmit electrical pulses to, forexample, a plurality of pins 110 or other similarly configuredelectrical conductors capable of transmitting an electrical pulse tocontacts 192 in the connection lumens. One end of pins 110 may connectwith the electronic circuitry of pulse generator 104 in a manner thatallows it to receive electrical pulses from the power source. Theopposite end of pins 110 may allow for the transfer of electrical energyfrom the pulse generator assembly 104 to the contacts 192 within theinsertion lumens. Further, the power source may include various typesand configurations of batteries, various configurations ofsuper-capacitors and such other power source technology that is known tothose skilled in the art for producing an electrical impulse. In anexemplary embodiment, the power source employs a rechargeable orreplenishable power source, such as a rechargeable battery or otherreplenishable power device. The particular type and configuration of thepower source may vary as contemplated by those skilled in the artwithout departing from the scope and spirit of the current invention.

Those of ordinary skill in the art will also recognize that a widevariety of configurations may be used to electrically transmitelectrical pulses from pulse generator 104 to electrical contacts 192without departing from the spirit and scope of the invention, including(in the case where connector block 150 is not joined directly to pulsegenerator assembly 104) electrical cables or leads extending from pins110, or alternatively directly attaching to generator assembly 104, thattransmit the electrical pulses to a remotely located connector block150. Further, the connector block 150 may include an electricalconnector plate that contacts the circuitry on one side and the contactsof the channel on the other side. It is further contemplated that thecomponents may provide for or assist with the connection of theconnector block 150 with the housing 106. The use of various mechanismsthat would further promote any of the above described features of thecurrent invention and allow the implementation of the implantablemedical device 100 in a manner similar to that described herein arecontemplated for use. Further, as a variety of configurations arereadily available and known to those of ordinary skill in the art forelectrically communicating a pulse generator with electrical contactswithin a connection lumen (such as those set forth in U.S. PatentApplication Publication No. 2006/0167522, the specification of which isherein incorporated by reference), such assembly is not further detailedhere.

The electronic circuitry of pulse generator 104 may preferably include acircuit board coupled to the power source and including variouselectronic components, which may include but are not limited to powercircuits and a microcontroller. Such microcontroller is preferablycapable of directing electrical pulses to specific pins 192 within eachof connection lumen 164 and connection lumen 174, and is likewiseprogrammable (such as by way of a remote, handheld programmercommunicating with telemetry circuitry in pulse generator 104) so as tostore particular electrical pulse generation profiles for use dependingon the lead configuration that is to be used with the IMD. Thus, by wayof non-limiting example, in the case where a single 12-contact lead isto be used, the microcontroller of pulse generator 104 may be programmedto deliver electrical pulses appropriate for each of the contacts onsuch 12-contact lead. Likewise, where both an 8-contact lead and a4-contact lead are to be used (each being inserted into an opposite endof the particular connection lumen), the microcontroller of pulsegenerator 104 may be programmed to deliver a first set of electricalpulses appropriate for the contacts of the 8-contact lead to eight ofthe contacts within the connection lumen, and to deliver a second set ofelectrical pulses appropriate for the contacts of the 4-contact lead tofour of the contacts within the same connection lumen. Those of ordinaryskill in the art will recognize that various other electrical pulsegeneration profiles may be desired for various patient conditions.

It is to be understood that connector block 150 described herein isexemplary and that various components, dimensional characteristicsand/or configurations may be modified and still fall within the scope ofthe current invention. For instance, alternative embodiments may includea connector block with one insertion lumen or three or more insertionlumens disposed within the casing.

It is further contemplated that one or both ends of an insertion lumenmay not have a lead inserted within it. Stops or plugs, such as plasticblanks, may be inserted into the opening of the unused end. Such plugsmay be sized to complement, and facilitate precise insertion of, thelead. For example, a 12-contact insertion lumen may be provided with aplug at one end whose length occupies 4 contact positions, such thatwhen an 8-contact lead is inserted so as to stop against the plug, it isat the correct depth. Alternatively, the length of the plug might occupyzero contacts, occluding only the end of the port, such as might bedesirable for use with a 12-contact lead.

The insertion end of the leads are inserted through the insert openingsof the insertion lumens in order to place contacts 220 on leads 200 and210 in electrical communication with electrical contacts 192 within theinsertion lumen. Overall, the configuration and dimensionalcharacteristics of the insertion lumens can be varied as may becontemplated by those skilled in the art without departing from thespirit and scope of the current invention.

It is further contemplated that a connector block 150 may include two ormore insertion lumens that are differently configured from one another.For example, the dimensional characteristics between the insertionlumens may vary. The number and configuration of electrical contactswithin the insertion lumens may also vary. It is further contemplatedthat the connector block 150 may include, for instance, three insertionlumens where one of the insertion lumens is an open-ended insertionlumen as described above, and the other two insertion lumens include aclosed second end.

The varying configurations available for the insertion lumens of thecurrent invention allow leads of various configurations to be receivedand operationally coupled with a pulse generator assembly to transmitelectrical stimulation provided by the implantable medical device to adesired portion of a patient's body. In the exemplary embodiment, and asparticularly shown in FIG. 1, first leads 200 include an insertion endhaving a plurality of contacts 220. Likewise, second leads 210 includean insertion end having a plurality of contacts 220. By way ofnon-limiting example, there may be 8 contacts located on each of firstleads 200, and 4 contacts located on each of second leads 210. Inalternative embodiments, any of the leads may include 12 contacts, 8contacts or various other numbers of contacts as may be required for aparticular application.

-   -   Those of ordinary skill in the art will recognize that in some        instances, particular applications may warrant the use of four        separate leads, which would correspond to the use of (again by        way of non-limiting example) a 4×6 configuration (in which 4        leads are used, each having 6 electrical contacts) or,        alternatively, a 2×4 configuration in combination with a 2×8        configuration (in which 4 leads are used, 2 having 4 electrical        contacts and 2 having 8 electrical contacts). In order to        simplify inventory, a lead manufacturer may desire to provide        only 8-contact leads, in which case the connector block 150 may        be configured to allow partial insertion (i.e., leaving two or        four contacts exposed outside of connector block 150) if only 6        or 4 contacts are to be used. The order and number of the        contacts at pulse generator 104 may, in turn, be programmed as        detailed above to provide for such connection, such that the tip        contact at the insertion end of the lead corresponds to the        appropriate electrical contact 192 within the insertion lumen.

It may also be desirable in certain applications to provide forinsertion of a lead into connector block 150 at varying depths so as toaccommodate different lead designs by different manufacturers, againconfiguring the electrical contacts 192 within the respective insertionlumens to correspond to the appropriate contacts on such lead. As shownin FIGS. 1-3, set screws 118 may be provided at both ends of each ofinsertion lumens 164 and 174 to assist in holding such leads in placeafter insertion, whether partial or whole, into the respective insertionlumen.

Each of the insertion ends of leads 200 and 210 are inserted into theinsert openings of the first or second ends of the first and secondinsertion lumens, respectively. As described above, the leads may beinserted simultaneously into both ends of a single insertion lumen. Oncethe insertion ends of leads 200 and 210 are fully inserted into theirrespective insertion lumens, the plurality of electrical contacts onthose insertion ends of leads 200 and 210 are positioned in electricalcommunication with the plurality of contacts 192 contained within therespective insertion lumen. In the exemplary embodiment shown in FIGS.1-3, the connector block 150 allows the simultaneous connection of fourleads with the implantable medical device 100, thereby further allowingelectrical stimulation to be provided to all four leads simultaneously.

In an exemplary embodiment, the end of the lead opposite the insertionend can terminate in varying configurations, such as an in-lineelectrode or contact paddle that provides varying configurations ofcontacts for direct application of the electrical stimulation to adesired location, such as a particular location on or in a patient'sbody. In one embodiment, the contacts may be provided on a paddle in,for example, a 3×8 configuration (the 3×8 configuration is in referenceto the number of columns and rows of individual contacts provided on thepaddle). In this embodiment, the 24 contacts may be wired to two12-contact insertion ends, which connect to two 12-contact insertionlumens on the connector block 150. In a contemplated alternativeembodiment, the contacts may be provided on three separate leads, eachof which may be inserted and connected with connector block 150independently; these may, by way of non-limiting example, be connectedto the same two 12-contact insertion lumens by inserting two 4-contactleads (which may terminate in an 8-contact female connector) into oneend of the two channels so as to accommodate one 8-contact leadextending from the paddle, while the other two leads are inserted intothe other end of the two insertion lumens.

By way of further example, the configuration of the contacts on a paddlemay alternatively be 4×6, or any other variety of electrodeconfigurations. Still further, the contacts may alternatively comprisean in-line percutaneous electrode similar to a wire, wherein theconductive section extends in an integral manner from the rest of thelead. Various other configurations as contemplated by those of ordinaryskill in the art may be employed without departing from the scope andspirit of the present invention.

Next, and with particularly reference to FIG. 4, so as to accommodate avariety of leads with different numbers of contacts and varying contactpad or in-line percutaneous electrode designs and configurations,adapters may be used with the current invention. For example, a “Y”cable adapter may be used having, for instance, an 8-contact male endand two 4-contact female ends, in which case the 8-contact male end maybe inserted into one end of a single insertion lumen, with pulsegenerator 104 being programmed to deliver electrical pulses to theappropriate contacts on the 8-contact male end so as to transmit theintended electrical pulses to the separate 4-contact female ends, whichin turn may separately transmit the received electrical pulses on toadditional leads and/or connector blocks attached to the 4-contactfemale ends. Alternatively, and with regard to a particular aspect ofthe invention as shown in FIG. 4, a “Y” cable adapter 300 may beconfigured with two 4-contact male ends 310 which may be inserted intoeach of two insertion lumens of connector block 150, while the oppositeend of the “Y” cable adapter may terminate in an 8-contact femalereceptacle 320 configured to receive an 8-contact insertion end of alead. In this novel configuration, the IMD could simultaneously supporta total of three 8-contact percutaneous leads, which percutaneous leadscould then be placed side-by-side to provide a minimally invasivetripole. Those of ordinary skill in the art will also recognize,however, that the adapter may include various numbers of contacts oneither end without departing from the spirit and scope of the invention.In particularly preferred embodiments, the adapter 300 may be eitherrigid or semi-rigid, may be integrated tightly into the connector block150, or alternatively may be integrated with the outer body of pulsegenerator assembly 104, such as by being coiled around a reel attachedto the outer body of pulse generator assembly 104, or removably housedwithin a shield or a bag 400 (FIG. 4) attached to one side of the outerbody of pulse generator assembly 104 within which redundant lead may becoiled. The operational use and connection scheme of the adapters mayvary as contemplated by those skilled in the art and may allow anynumber of leads to be connected to a power source (described below) ofthe IMD 100 of the current invention.

In the exemplary embodiment shown in FIGS. 1-3, the pulse generatorassembly 104 includes a housing 106, otherwise commonly referred to as a“casing” or “can”. In one embodiment, the housing 106 may be integrallyformed with the connector block 150. Alternatively, connector block 150may be connected with the housing 106 in a manner that allows theremoval of the connector block 150. Thus, similarly or differentlyconfigured housings 106 and connector blocks 150 may be interconnectedwith one another and fall within the scope of the current invention solong as at least one insertion lumen open at both ends is includedwithin the connector block. Thus, the current invention contemplatesthat the configuration of the IMD 100 may be varied without departingfrom the spirit and scope of the invention.

Various connection mechanism(s) as contemplated by those skilled in theart may be employed by the current invention to allow theinterchangeability of the housing 106 and connector block 150. Forexample, a compression lock assembly may be employed where the connectorblock 150 may include a compressive device or receiver that connectswith a receiver or compressive device included on the housing 106. Otherconnection mechanisms, such as a snap-fit, friction-fit or otherwiseknown to those skilled in the art may likewise be employed by thecurrent invention. Thus, it is contemplated that the positioning of thevarious components of the various connection mechanisms used to attachthe connector block 150 to the housing 106 will be complimentary to oneanother.

Likewise, as shown in FIG. 5, connector block 150 may be provided as anentirely separate structure from a housing 106 and connected thereto viaone or more electrical cables 310. In this case, electrical cables 310in one embodiment may provide an extended electrical connection betweenpulse generator assembly 104 within housing 106, and contacts 192 ininsertion lumens 164 and 174, in which case electrical cables 310 may bedirected into housing 106 to directly engage pulse generator assembly104. Alternatively, electrical cables 310 may terminate in leadsconfigured for insertion into insertion lumens on an IMD header oftraditional configuration.

With regard to an embodiment of the invention, and with particularreference to FIG. 6, a connector block 450 may alternatively be formedin a modular assembly including a lower casing 452 having a firstinsertion lumen 464 and a second insertion lumen 474 extending throughcasing 452, wherein each of first insertion lumen 464 and secondinsertion lumen 474 have a plurality of electrical contacts 492 thatagain connect with circuitry of the pulse generator assembly 104allowing the electrical stimulation to pass through to the plurality ofelectrical contacts 492, all as described in greater detail above.However, each of first insertion lumen 464 and second insertion lumen474 are formed as preferably half cylinders having an open top, thusallowing a lead to be laid or pressed down into the desired insertionlumen instead of requiring a longitudinal insertion of the lead into theinsertion lumen. By allowing the lead to be so laid down into thechannels formed by each of insertion lumen 464 and insertion lumen 474,the operator may visually align the contacts 220 on a lead with theelectrical contacts 492 in order to obtain the desired alignment (i.e.,the desired longitudinal position of the lead 200 or 210 within theassociated insertion lumen 464 or 474) without requiring the operator toguess as to alignment or to use a stop inserted in the opposite end ofthe respective insertion lumen. Once the operator has so laid the leador leads in the desired insertion lumens 464 and/or 474, an upper casing454 may be placed on top of and tightly joined to lower casing 452 toseal the casings together, forming a closed, complete connector block450. Upper casing 454 may be configured as a cap, lid, membrane, oradhesive layer that seals and completes connector block 450. Uppercasing 454 may be joined to lower casing 452 in various manners toprovide a completely sealed, biologically inert connector block 450. Forinstance, and by way of non-limiting example, one or more threadedconnectors 418 (e.g., a screw or bolt) may be inserted though one ormore openings 417 in upper casing 454 and into threaded receivers 417 onlower casing 464 in order to removably attach upper casing 454 to lowercasing 452. Of course, those of ordinary skill in the art will recognizethat other connector devices, such as compression locking mechanisms orfriction fit locking mechanisms, may be used without departing from thespirit and scope of the invention.

Optionally, modular connector block 450 may include an adapter 500configured to allow all leads that an operator desires to connect to asingle pulse generator assembly 104 to extend from the connector block450 in a single direction, rather than from opposite ends of theconnector block 450. Adapter 500 may including a casing 562 having alead insertion lumen 564 extending therethrough (of similarconfiguration to lead insertion lumens 464 and 474). Lead insertionlumen 564 may, in turn, be provided a first set of electrical contacts569 and a second set of electrical contacts 570, each of which areconfigured to deliver an electrical pulse to a lead positioned withininsertion lumen 564. In order to electrically interconnect suchelectrical contacts 569 and 570 with the circuitry of pulse generatorassembly 104, each of the sets of electrical contacts 569 and 570 are inelectrical communication with a lead connector assembly 510 comprising afirst lead segment 510A and a second lead segment 510B of substantiallyidentical configuration. One end of first lead segment 510A ispreferably in the form of a traditional electrical lead, having aplurality of contacts 513 situated along the terminating length of leadsegment 510A. The opposite end of first lead segment 510A extends intocasing 562, and in turn establishes an electrical connection betweencontacts 513 and the first set of electrical contacts 569 in insertionlumen 564 via electrical conductors 514. Similarly, one end of secondlead segment 510B is preferably in the form of a traditional electricallead, having a plurality of contacts 517 situated along the terminatinglength of lead segment 510B. The opposite end of second lead segment510B extends into casing 562, and in turn establishes an electricalconnection between contacts 517 and the second set of electricalcontacts 570 in insertion lumen 564 via electrical conductors 518. Eachof lead segments 510A and 510B are configured for insertion intoinsertion lumens 464 and 474 of lower casing 452, such that the contacts513 and 517 of lead segments 510A and 510B, respectively, may be placedin contact with electrical contacts 492 of insertion lumens 464 and 474.As a result, when pulse generator assembly 104 supplies an electricalpulse to the corresponding contacts 492 in insertion lumens 464 and 474,that electrical pulse is in turn passed to lead segments 510A and 510B,and on to contacts 569 and 570 within insertion lumen 564 of adapter500. Those electrical pulses may, in turn, then be transferred to a leadpositioned within insertion lumen 564. With this configuration, if anoperator wishes to deploy multiple leads, two of which have a number ofcontacts 220 less than the number of electrical contacts 492 ininsertion lumens 464 and 474, those leads may be placed in insertionlumens 464 and 474, and the remaining electrical contacts 492 may beused to supply a third lead positioned in insertion lumen 564 in adapter500, thus allowing all of such leads to extend in the same directionfrom connector block 450. This configuration may make removal,insertion, lead adjustment and/or replacement easier for a user of thedevice.

Alternatively, instead of electrically connecting electrical contacts569 and 570 of insertion lumen 564 with electrical contacts 492 ofinsertion lumens 464 and 474 through the use of external lead segments510A and 510B, direct, internal connections may optionally be provided.In this configuration, and with reference to FIG. 8, two rows ofcontacts 520 may extend outward from the bottom of adapter 500 and arepreferably configured to sit within insertion lumens 464 and 474 oflower segment 452 of connector block 450 where they may be placed inelectrical communication with electrical contacts 492. Within adapter500, one row of contacts 520 is in electrical communication with thefirst set of electrical contacts 569 in insertion lumen 564 viaelectrical conductors 514, while the other row of contacts 520 is inelectrical communication with the second set of electrical contacts 570in insertion lumen 564 via electrical conductors 518. By providing suchinternally situated contacts 520, the use of extraneous cablingassociated with lead segments 510A and 510B may optionally be avoided,providing a more compact and potentially more easily manufacturedconnector block 450.

As yet another alternative, while FIG. 7 particularly shows adapter 500configured as a separate layer sandwiched between lower casing 452 andupper casing 454, those of ordinary skill in the art will recognize thatfirst casing 452 could alternatively be configured with a thirdinsertion lumen extending parallel to insertion lumens 464 and 474 andhaving internal electrical contacts wired in parallel with electricalcontacts 492 in each of insertion lumens 464 and 474. More particularly,one half of the electrical contacts in the third insertion lumen may bewired in parallel with four electrical contacts 492 in insertion lumen464, while the remaining half of the electrical contacts in the thirdinsertion lumen may be wired in parallel with four electrical contacts492 in insertion lumen 474. Preferably, those contacts in insertionlumens 464 and 474 that are so wired to the electrical contacts in thethird insertion lumen are contacts positioned at an end of each of therespective insertion lumens. In this case, and with regard to theparticular exemplary configuration shown in FIG. 7, connector block 450may optionally be used as either a 2×12 connector, or a 3×8 connector(in which case the two eight-contact leads in insertion lumens 464 and474 do not engage the last four electrical contacts 492, and a thirdeight-contact lead placed within the third insertion lumen will receivethe electrical signal supplied by the pulse generator assembly 104 tothe open electrical contacts 492 in insertion lumens 464 and 474), ineach case with all leads extending from connector block 450 in a commondirection.

Other than the modular, sandwich-type assembly of connector block 450,all other features of connector block 450 are substantially identical tothe features described above with respect to connector block 150 ofFIGS. 1-5, including by way of non-limiting example the configuration ofelectrical contacts 492 within each of insertion lumens 464 and 474, andthe interconnection of such electrical contacts 492 with the circuitryof pulse generator assembly 104, such that the discussion aboveregarding such features is equally applicable to the embodiments thatcomprise such modular, sandwich-type assembly of connector block 450.

Moreover, those of ordinary skill in the art will recognize that thedimensions and configuration of the various components of the adapter500 and of connector block 450 may be varied to accommodate the use ofvarious different leads and/or header assemblies without departing fromthe spirit and scope of the invention. For instance, alternativeembodiments may include an adapter 500 with multiple insertion lumens ofvarious dimensions disposed within the casing.

Having now fully set forth the preferred embodiments and certainmodifications of the concept underlying the present invention, variousother embodiments as well as certain variations and modifications of theembodiments herein shown and described will obviously occur to thoseskilled in the art upon becoming familiar with said underlying concept.It should be understood, therefore, that the invention may be practicedotherwise than as specifically set forth herein.

I claim:
 1. A connector assembly for removably attaching a plurality ofleads to an implantable medical device, comprising: a connector blockhousing having a first end and a second end, said connector blockhousing further comprising a lower casing and an upper casing removablyattached to said lower casing; and a first lead insertion lumenextending through said connector block housing from said first end tosaid second end and providing two lead points of entry through saidconnector block housing and into said first lead insertion lumen, saidfirst lead insertion lumen configured to simultaneously accept leadsinserted through each of said first end and said second end, said firstlead insertion lumen comprising a plurality of electrical lumen contactsdisposed within said first lead insertion lumen and configured to directa electrical pulses from a pulse generator assembly to leads positionedwithin said first lead insertion lumen, and wherein said first leadinsertion lumen is reconfigurable to, in a first instance, directelectrical pulses to only first and second leads having first and secondnumbers of electrical lead contacts, and alternatively in a secondinstance, to direct electrical pulses to only third and fourth leadshaving third and fourth numbers of electrical lead contacts that aredifferent from said first and second numbers of electrical leadcontacts.
 2. The connector assembly of claim 1, said first leadinsertion lumen defining a first opening within said first end of saidconnector block housing and a second opening within said second end ofsaid connector block housing.
 3. The connector assembly of claim 2,wherein each of said first and second openings are configured to receivea proximal end of a lead.
 4. The connector assembly of claim 1, whereinsaid connector block housing is attached to and hermetically sealed witha pulse generator assembly housing containing a pulse generatorassembly.
 5. The connector assembly of claim 4, wherein said pulsegenerator assembly is programmable to direct an electrical pulse to atleast one of said electrical lumen contacts within said lead insertionlumen.
 6. The connector assembly of claim 4, wherein said pulsegenerator assembly is programmable to direct a first electrical pulse toa first plurality of electrical lumen contacts in contact with saidfirst lead within said first lead insertion lumen, and to simultaneouslydirect a second electrical pulse to a second plurality of electricallumen contacts in contact with said second lead within said first leadinsertion lumen.
 7. The connector assembly of claim 6, wherein saidfirst plurality of electrical lumen contacts are configured to transfersaid first electrical pulse to said first lead positioned within saidfirst lead insertion lumen, and said second plurality of electricallumen contacts are configured to simultaneously transfer said secondelectrical pulse to said second lead positioned within said first leadinsertion lumen.
 8. The connector assembly of claim 1, wherein saidconnector block housing is remotely connected to a pulse generatorassembly housing containing a pulse generator assembly.
 9. The connectorassembly of claim 8, wherein said pulse generator assembly isprogrammable to direct an electrical pulse to at least one of saidelectrical lumen contacts within said lead insertion lumen.
 10. Theconnector assembly of claim 8, wherein said pulse generator assembly isprogrammable to direct a first electrical pulse to a first plurality ofelectrical lumen contacts in contact with said first lead within saidfirst lead insertion lumen, and to simultaneously direct a secondelectrical pulse to a second plurality of electrical lumen contacts incontact with said second lead within said first lead insertion lumen.11. The connector assembly of claim 10, wherein said first plurality ofelectrical lumen contacts are configured to transfer said firstelectrical pulse to said first lead positioned within said first leadinsertion lumen, and said second plurality of electrical lumen contactsare configured to simultaneously transfer said second electrical pulseto said second lead positioned within said first lead insertion lumen.12. The connector assembly of claim 8, wherein said connector blockhousing is in electrical connection with said pulse generator assemblyhousing through at least one electrical interconnect cable.
 13. Theconnector assembly of claim 12, wherein said electrical interconnectcable terminates at one end within said pulse generator assemblyhousing.
 14. The connector assembly of claim 12, wherein said electricalinterconnect cable terminates at one end in a lead configured forinsertion into a lead connector port of said pulse generator assemblyhousing.
 15. The connector assembly of claim 1, said connector blockhousing further comprising an adapter positioned between said lowercasing and said upper casing and having an adapter lead insertion lumenextending into said adapter, said adapter lead insertion lumen furthercomprising a plurality of electrical contacts disposed within saidadapter lead insertion lumen and in electrical communication with atleast some of said electrical lumen contacts within said first leadinsertion lumen.
 16. The connector assembly of claim 15, furthercomprising at least one lead segment electrically communicating aportion of said electrical lumen contacts within said first leadinsertion lumen with a first portion of said electrical contactsdisposed within said adapter lead insertion lumen.
 17. The connectorassembly of claim 16, further comprising: a second lead insertion lumenextending through said connector block housing from said first end tosaid second end, said second lead insertion lumen further comprising asecond plurality of electrical contacts disposed within said second leadinsertion lumen; and a second lead segment electrically communicating aportion of said electrical contacts within said second lead insertionlumen with a second portion of said electrical contacts disposed withinsaid adapter lead insertion lumen.
 18. The connector assembly of claim15, said adapter further comprising at least a first plurality ofadapter contacts configured to engage with a portion of said electricallumen contacts within said first lead insertion lumen so as toelectrically communicate said portion of said electrical lumen contactswithin said first lead insertion lumen with a first portion of saidelectrical contacts disposed within said adapter lead insertion lumen.19. The connector assembly of claim 18, further comprising: a secondlead insertion lumen extending through said connector block housing fromsaid first end to said second end, said second lead insertion lumenfurther comprising a second plurality of electrical contacts disposedwithin said second lead insertion lumen; and a second plurality ofadapter contacts configured to engage with a portion of said electricalcontacts within said second lead insertion lumen so as to electricallycommunicate said portion of said electrical contacts within said secondlead insertion lumen with a second portion of said electrical contactsdisposed within said adapter lead insertion lumen.
 20. An implantablemedical device configured to receive a plurality of leads, comprising: apulse generator assembly housing containing a pulse generator assembly;a connector block housing in electrical communication with said pulsegenerator housing and having a first end and a second end, saidconnector block housing further comprising a lower casing and an uppercasing removably attached to said lower casing; and at least one leadinsertion lumen extending through said connector block housing from saidfirst end to said second end and providing two points of entry throughsaid connector block housing and into said lead insertion lumen, saidlead insertion lumen configured to simultaneously accept leads insertedthrough each of said first end and said second end, said first leadinsertion lumen comprising a plurality of electrical lumen contactsdisposed within said lead insertion lumen and configured to directelectrical pulses from said pulse generator assembly to leads positionedwithin said lead insertion lumen, and wherein said at least one leadinsertion lumen is reconfigurable to, in a first instance, directelectrical pulses to only first and second leads having first and secondnumbers of electrical lead contacts, and alternatively in a secondinstance, to direct electrical pulses to only third and fourth leadshaving third and fourth numbers of electrical lead contacts that aredifferent from said first and second numbers of electrical leadcontacts.
 21. The implantable medical device of claim 20, said leadinsertion lumen defining a first opening within said first end of saidconnector block housing and a second opening within said second end ofsaid connector block housing.
 22. The implantable medical device ofclaim 20, wherein said connector block housing is attached to andhermetically sealed with said pulse generator assembly housing.
 23. Theimplantable medical device of claim 22, wherein said pulse generatorassembly is programmable to direct an electrical pulse to at least oneof said electrical lumen contacts within said lead insertion lumen. 24.The implantable medical device of claim 22, wherein said pulse generatorassembly is programmable to direct a first electrical pulse to a firstplurality of electrical lumen contacts in contact with said first leadwithin said lead insertion lumen, and to simultaneously direct a secondelectrical pulse to a second plurality of electrical lumen contacts incontact with said second lead within said lead insertion lumen.
 25. Theimplantable medical device of claim 24, wherein said first plurality ofelectrical lumen contacts are configured to transfer said firstelectrical pulse to said first lead positioned within said leadinsertion lumen, and said second plurality of electrical lumen contactsare configured to simultaneously transfer said second electrical pulseto said second lead positioned within said lead insertion lumen.
 26. Theimplantable medical device of claim 20, wherein said connector blockhousing is remotely connected to said pulse generator assembly housing.27. The implantable medical device of claim 26, wherein said pulsegenerator assembly is programmable to direct an electrical pulse to atleast one of said electrical lumen contacts within said lead insertionlumen.
 28. The implantable medical device of claim 26, wherein saidpulse generator assembly is programmable to direct a first electricalpulse to a first plurality of electrical lumen contacts in contact withsaid first lead within said lead insertion lumen, and to simultaneouslydirect a second electrical pulse to a second plurality of electricallumen contacts in contact with said second lead within said leadinsertion lumen.
 29. The implantable medical device of claim 28, whereinsaid first plurality of electrical lumen contacts are configured totransfer said first electrical pulse to said first lead positionedwithin said lead insertion lumen, and said second plurality ofelectrical lumen contacts are configured to simultaneously transfer saidsecond electrical pulse to said second lead positioned within said leadinsertion lumen.
 30. The implantable medical device of claim 26, whereinsaid connector block housing is in electrical connection with said pulsegenerator assembly housing through at least one electrical interconnectcable.
 31. The implantable medical device of claim 30, wherein saidelectrical interconnect cable terminates at one end within said pulsegenerator assembly housing.
 32. The implantable medical device of claim30, wherein said electrical interconnect cable terminates at one end ina lead configured for insertion into a lead connector port of said pulsegenerator assembly housing.
 33. The implantable medical device of claim20, said connector block housing further comprising an adapterpositioned between said lower casing and said upper casing and having anadapter lead insertion lumen extending into said adapter, said adapterlead insertion lumen further comprising a plurality of electricalcontacts disposed within said adapter lead insertion lumen and inelectrical communication with at least some of said electrical lumencontacts within said lead insertion lumen.
 34. The implantable medicaldevice of claim 33, further comprising at least one lead segmentelectrically communicating a portion of said electrical lumen contactswithin said lead insertion lumen with a first portion of said electricalcontacts disposed within said adapter lead insertion lumen.
 35. Theimplantable medical device of claim 34, further comprising: a secondlead insertion lumen extending through said connector block housing fromsaid first end to said second end, said second lead insertion lumenfurther comprising a second plurality of electrical contacts disposedwithin said second lead insertion lumen; and a second lead segmentelectrically communicating a portion of said electrical contacts withinsaid second lead insertion lumen with a second portion of saidelectrical contacts disposed within said adapter lead insertion lumen.36. The implantable medical device of claim 33, said adapter furthercomprising at least a first plurality of adapter contacts configured toengage with a portion of said electrical lumen contacts within said leadinsertion lumen so as to electrically communicate said portion of saidelectrical lumen contacts within said lead insertion lumen with a firstportion of said electrical contacts disposed within said adapter leadinsertion lumen.
 37. The implantable medical device of claim 36, furthercomprising: a second lead insertion lumen extending through saidconnector block housing from said first end to said second end, saidsecond lead insertion lumen further comprising a second plurality ofelectrical contacts disposed within said second lead insertion lumen;and a second plurality of adapter contacts configured to engage with aportion of said electrical contacts within said second lead insertionlumen so as to electrically communicate said portion of said electricalcontacts within said second lead insertion lumen with a second portionof said electrical contacts disposed within said adapter lead insertionlumen.
 38. A method for delivering an electrical pulse to a targetedlocation, comprising: providing an implantable medical device configuredto receive a plurality of leads, said implantable medical devicecomprising: a pulse generator assembly housing containing a pulsegenerator assembly; a connector block housing in electricalcommunication with said pulse generator housing and having a first endand a second end, said connector block housing further comprising alower casing and an upper casing removably attached to said lowercasing; and at least one lead insertion lumen extending through saidconnector block housing from said first end to said second end andproviding two points of entry through said connector block housing andinto said lead insertion lumen, said lead insertion lumen configured tosimultaneously accept leads inserted through each of said first end andsaid second end, said first lead insertion lumen comprising a pluralityof electrical lumen contacts disposed within said lead insertion lumenand configured to direct electrical pulses from said pulse generatorassembly to leads positioned within said lead insertion lumen, andwherein said at least one lead insertion lumen is reconfigurable to, ina first instance, direct electrical pulses only to first and secondleads having first and second numbers of electrical lead contacts, andalternatively in a second instance, to direct electrical pulses to onlythird and fourth leads having third and fourth numbers of electricallead contacts that are different from said first and second numbers ofelectrical lead contacts; implanting said implantable medical devicewithin a patient; and programming said implantable medical device todeliver an electrical pulse to a target location within said patient.39. The method of claim 38, wherein said connector block housing isattached to and hermetically sealed with said pulse generator assemblyhousing.
 40. The method of claim 39, wherein said pulse generatorassembly is programmable to direct an electrical pulse to at least oneelectrical lumen contact within said lead insertion lumen.
 41. Themethod of claim 40, wherein said programming step comprises programmingsaid pulse generator assembly to direct an electrical pulse to at leastone electrical lumen contact of said plurality of electrical lumencontacts within said lead insertion lumen.
 42. The method of claim 39,wherein said pulse generator assembly is programmable to direct a firstelectrical pulse to a first plurality of electrical lumen contacts incontact with said first lead within said lead insertion lumen, and tosimultaneously direct a second electrical pulse to a second plurality ofelectrical contacts in contact with said second lead within said leadinsertion lumen.
 43. The method of claim 42, wherein said firstplurality of electrical lumen contacts are configured to transfer saidfirst electrical pulse to said first lead positioned within said leadinsertion lumen, and said second plurality of electrical lumen contactsare configured to simultaneously transfer said second electrical pulseto said second lead positioned within said lead insertion lumen.
 44. Themethod of claim 43, wherein said programming step comprises programmingsaid pulse generator assembly to direct a first electrical pulse to saidfirst plurality of electrical lumen contacts in contact with said firstlead within said lead insertion lumen, and to simultaneously direct asecond electrical pulse to a second plurality of electrical lumencontacts in contact with said second lead within said lead insertionlumen.
 45. The method of claim 38, wherein said connector block housingis remotely connected to said pulse generator assembly housing.
 46. Themethod of claim 45, wherein said pulse generator assembly isprogrammable to direct an electrical pulse to at least one electricallumen contact within said lead insertion lumen.
 47. The method of claim46, wherein said programming step comprises programming said pulsegenerator assembly to direct an electrical pulse to at least oneelectrical lumen contact of said plurality of electrical lumen contactswithin said lead insertion lumen.
 48. The method of claim 45, whereinsaid pulse generator assembly is programmable to direct a firstelectrical pulse to a first plurality of electrical lumen contacts incontact with said first lead within said lead insertion lumen, and tosimultaneously direct a second electrical pulse to a second plurality ofelectrical lumen contacts in contact with said second lead within saidlead insertion lumen.
 49. The method of claim 48, wherein saidprogramming step comprises programming said pulse generator assembly todirect a first electrical pulse to said first plurality of electricallumen contacts in contact with said first lead within said leadinsertion lumen, and to simultaneously direct a second electrical pulseto said second plurality of electrical lumen contacts in contact withsaid second lead within said lead insertion lumen.
 50. The method ofclaim 49, wherein said first plurality of electrical lumen contacts areconfigured to transfer said first electrical pulse to said first leadpositioned within said lead insertion lumen, and said second pluralityof electrical lumen contacts are configured to simultaneously transfersaid second electrical pulse to said second lead positioned within saidlead insertion lumen.
 51. The method of claim 45, wherein said connectorblock housing is in electrical connection with said pulse generatorassembly housing through at least one electrical interconnect cable. 52.The method of claim 51, wherein said electrical interconnect cableterminates at one end within said pulse generator assembly housing. 53.The method of claim 51, wherein said electrical interconnect cableterminates at one end in a lead configured for insertion into a leadconnector port of said pulse generator assembly housing.
 54. The methodof claim 38, wherein said connector block housing further comprises anadapter positioned between said lower casing and said upper casing andhaving an adapter lead insertion lumen extending into said adapter, saidadapter lead insertion lumen further comprising a plurality ofelectrical contacts disposed within said adapter lead insertion lumenand in electrical communication with at least some of said electricallumen contacts within said lead insertion lumen.
 55. The method of claim54, further comprising at least one lead segment electricallycommunicating a portion of said electrical lumen contacts within saidlead insertion lumen with a first portion of said electrical contactsdisposed within said adapter lead insertion lumen.
 56. The method ofclaim 55, wherein said connector block housing further comprises: asecond lead insertion lumen extending through said connector blockhousing from said first end to said second end, said second leadinsertion lumen further comprising a second plurality of electricalcontacts disposed within said second lead insertion lumen; and a secondlead segment electrically communicating a portion of said electricalcontacts within said second lead insertion lumen with a second portionof said electrical contacts disposed within said adapter lead insertionlumen.
 57. The method of claim 55, wherein said adapter furthercomprises at least a first plurality of adapter contacts configured toengage with a portion of said electrical lumen contacts within said leadinsertion lumen so as to electrically communicate said portion of saidelectrical lumen contacts within said lead insertion lumen with a firstportion of said electrical contacts disposed within said adapter leadinsertion lumen.
 58. The method of claim 57, wherein said connectorblock housing further comprises: a second lead insertion lumen extendingthrough said connector block housing from said first end to said secondend, said second lead insertion lumen further comprising a secondplurality of electrical contacts disposed within said second leadinsertion lumen; and a second plurality of adapter contacts configuredto engage with a portion of said electrical contacts within said secondlead insertion lumen so as to electrically communicate said portion ofsaid electrical contacts within said second lead insertion lumen with asecond portion of said electrical contacts disposed within said adapterlead insertion lumen.
 59. The method of claim 38, further comprising thestep of placing distal ends of said first and second leads or of saidthird and fourth leads at said target location within said patient. 60.The method of claim 38, wherein said first, second, third, or fourthleads have fewer electrical lead contacts than the plurality ofelectrical lumen contacts in said lead insertion lumen.
 61. The methodof claim 38, further comprising the step of placing distal ends of saidfirst and second leads or of said third and fourth leads at a secondtarget location.